[mkeroppi]

Ok, so I've done some RMAA testing on the X5 to check on the "line out" issue from the previous thread: http://www6.head-fi.org/forums/showthread.php?t=132688

The test result is here:
http://mkeroppi.com/iaudio/Comparison.htm

These tests are done by recording thru a Behringer mixer (which does not have that good of RMAA it self), so the Echo Mia result should be used as a guideline for comparison. All devices are recorded using 24/48 from the Echo Mia input. The Mia output also uses 24/48 instead of 16/44.1 as all others.

The result is basically, the lineout on the X5 is wrong (who knows what they did with it); however, the headphone output is fine for all practical purposes. Also, the line level of the X5 is -10dBu (the Audigy2 is 1Vrms, the Mia is +4dBV). Headphone out at max volume (40) has the same line voltage as line out.

 

[uncle b]

Though no audiologist myself...I know what sounds good to my ears...and with the X5, I prefer listening to an amp through the headphone out...the subpack just sounds weird, which was disappointing coming from an iRiver iHP-120 with the optical out.

 

[roy_jones]

I'm still not conceptually able to distill many useful inferences from looking at the RMAA stuff. So I appreciate the commentary about the results- because the results themselves, in graph form, don't mean a whole lot to me.

I'm surprised you're running your amp out of the headphone jack of the X5. At this point, I figure I'm either going to do that, once my X5 arrives, or I'm going to just sell my amp all together. What 'real-world' audio difference are you perceiving by running an external amp out of the headphone line? vs. non-amped. It strikes me as so counter-intuitive that it would be plausible to run an amp from the HP and not mess up the sound.

There was a post yesterday about someone determining that the line-out of the Ipod was functionally equivalent, due to the amp design, to the Ipod headphone line. I'm sure that's open to debate, but it makes me wonder whether the same could be true of the X5...and whether it's still possible to run the amp without taking a significant hit on SQ out of the headphone line.

Is the difference dramatic, between the H120, when you had it, vs. the X5? I truly wonder whether I made the right decision in buying the X5, considering you've got to essentially run it without a functional line-out.

 

[wolfen68]

Quote:

Originally Posted by roy_jones I'm surprised you're running your amp out of the headphone jack of the X5. At this point, I figure I'm either going to do that, once my X5 arrives, or I'm going to just sell my amp all together. What 'real-world' audio difference are you perceiving by running an external amp out of the headphone line? vs. non-amped. It strikes me as so counter-intuitive that it would be plausible to run an amp from the HP and not mess up the sound. .

If you have current hungry phones, the amp would still allow the phones to run at a better performance level....even if it is just "re-amping" the signal from the headphone out.

If you are using phones that are easily driven (to full performance) from the existing head-out, than there would be no point in amping out of the head-out.

The only benefit to amping already efficient headphones is to take advantage of the usually cleaner signal from the line-out.....which is apparently not the case with the X5.

 

[blessingx]

Interesting results mkeroppi. Thanks for posting.

 

[mkeroppi]

The thing is, the so-called "headphone out" is suppose to be lineout plus your amp. Any reasonable loads should play with no significant hit in SQ. The reason I've switched from the iPod is because its headphone out is not amped (current buffered). In that sense, the headphone out is the same as the lineout (which is probably true in the circuit schematics also, except for the volume control).

With that said, there's no problem to use an external amp with the headphone out, as you've only cascading 2 amps basically. So it's easy to speculate that iPod is cleaner with an amp it doesn't amp itself, so you get rid of one noisy, distortion pronge stage, though X5's headphone out does look that bad.

There were tests that says the X5 also have the iPod bass roll-off with low impedence headphones, I certainly don't really hear it, but I have yet to see correctly done RMAA to support or refute this.

One more thing, I believe your ears are the tools to find possible problems, and it takes good objective, repeatable, qualitative measurements to say what's the problem. The sound can be "weird", but with RMAA, I can authoritatively say X5's line out is "defective", and Ipod's headphone out is "crippled". There's no confusing audiophile vocabulary and "if you like the sound" in between the lines. BTW: Correctly done A/B tests only tell you the what, not the why, and subjective listening doesn't tell you anything except maybe possible whats.

 

[jant71]

In my limited experience, iAudio players don't work very well with external equipment. They achieve a good sound but seem to be designed to perform best with earbuds and easy to drive headphone. For full size headphones or external equipment I always grabbed another player.

 

[wolfen68]

I've seen a lot of talk about the lineout lack of quality on the X5 (bass fallout or whatever). Did the older iAudio models exhibit the same problems (such as M3)?

Are there any indications that iAudio is working on this? I see DAPReview mentions that a new scaled down version of the X5 is coming.....will they put the lineout on board and get it working the way it should?

This issue is the sole reason I have not gotten an X5. I need a good lineout (and 30 gig is a little small).